KIEV – By any standards, the drumbeat of growing tensions between Russia and Ukraine this month has been especially ominous.

It began as Russian President Vladimir Putin accused Kiev of embracing the “tactics of terror,” after Russia claimed to have caught Ukrainian saboteurs in Crimea. Ukrainian President Petro Poroshenko put troops on alert and warned the country might have to move toward martial law and mobilization if the conflict in the east or Crimea escalated.

Russia is now set to hold large military drills in the region next month. And in east Ukraine, the use of heavy weapons between Russian-backed separatists and the army has increased as opposing trenches have crept so close that opposing fighters can shout across the breach.

While the alleged incident in Crimea this month has not led to open conflict, Analysts say tensions are at their highest since the signing of what are known as the Minsk agreements in February 2015.

Once seen as a road map to end the conflict in east Ukraine, army officers now describe the accords have been described by army officers as “dead,” an International Crisis Group report said this month. And in Kiev, it is not unusual to hear once again that Russia is preparing to invade Ukraine.

“We view it as a real threat,” said Mikhail Samus, the deputy director for international affairs at the Kiev-based Center for Army, Conversion and Disarmament Studies, noting that a Russian Security Council meeting led by Putin in Crimea this weekend increased concerns of an escalation. “Putin is controlling the situation and that makes it the most dangerous situation.”

Last week’s The incident earlier this month, the facts of which are hotly disputed, appeared to be a possible flash point. Russia claims that Ukrainian intelligence staged a high-level raid led by a former soldier, and now truck driver Yevgeny Panov. Ukrainian troops also fired across the border, Russia said, and two Russian servicemen were killed.

Ukraine said the incident was invented. Later, a senior military intelligence officer told Poroshenko that Russian soldiers had shelled themselves.

The truth likely lies somewhere in between.

“Whether Crimea happened or did not happen does not matter anymore,” said Michael Kofman, a fellow at the Kennan Institute of the Wilson Center who focuses on post-Soviet security issues. “Russia can make it real by simply reacting to it as though it was real.”

Alex Ryabchyn, a member of Ukraine’s parliament, said Putin is looking to send a “signal to the West” to return to the negotiating table over Ukraine, believing that Kiev’s western partners are losing patience with Kiev amid the U.S. elections, the migration crisis and other urgent issues.

“What will you do if I attack or take some anti-terrorist measures?” Ryabchyn said. “Will you invade? Will you express concern? Let’s start negotiating, because I can choose to do this or not to do this at any time.”

Russia quickly posed the attacks as cause to refocus attention on the Minsk accords. Putin, in remarks from Crimea on Friday, said that the reason for the attack in Crimea was clear: “Because Ukraine is either unwilling or unable for some reason to implement the Minsk agreements.”

The accords include the approval of a “special status” for the Donbass region in eastern Ukraine and local elections whose terms remain disputed and largely favorable to Moscow. Kiev, in turn, has demanded return of control of the country’s eastern borders with Russia, a conduit for weapons, men, and other contraband, from rebel to Ukrainian control.

“Ukraine doesn’t have much interest in implementing Minsk,” Kofman said, noting growing appetite in Kiev to freeze the conflict in Donbass. “And my sense of this Crimea incident is that the Russians are trying to find some kind of leverage with the Europeans,” who are part of the negotiations.

With new deadlines for the European Union to renew sanctions against Russia approaching and little progress made on the accords, Russia may have decided to “scare the hell” out of the West, he said.

Violence in east Ukraine has also risen during the summer months. An International Crisis Group report released last week said that the 310-mile line of separation between the Ukrainian and separatist sides is “not fit for purpose,” and that the Minsk agreements are “being violated daily and heavily.”